Although the Cosmos get most of the attention and exposure, the Vancouver Whitecaps, who play Team America today at RFK Stadium at 2:30 p.m., have quietly become the best team in the North American Soccer League.

The Whitecaps have qualified for the playoffs the past six seasons, winning the Soccer Bowl in 1979, and have a 129-77 record during that span.

This season they own the league's best record (17-4) and have accumulated 136 points, 22 more than the Cosmos.

"We've been on top of the league all season," said striker David Cross. "If we slip up and finish second, then we've failed. Anything less than first place is no good to us."

Today's game will be a contrast of the old and new philosophies of the league . Team America is at the forefront of the league's Americanization drive.

Since their inception in 1974, the Whitecaps have been almost exclusively a British team.

Their current roster lists nine players from Great Britain, all of whom start, and only two from the United States.

As would be expected of a team dominated with British players, the Whitecaps have the league's best defense.

The team has given up only 20 goals, eight fewer than second-place Team America.

Whitecaps goalkeeper Tino Lettieri, the league leader in 1982 with a 1.23 goals-against average, is first again this season at 0.74.

Lettieri's eight shutouts also lead the league.

Vancouver has played surprisingly well on offense this season, considering its top scorer last year, Ray Hankin, finished 26th in the league.

Cross, bought from Manchester City of the English first division, leads the team with 13 goals, including 12 in his last 12 games, and has 29 points.

Carl Valentine is second with six goals and nine assists and midfielder Peter Beardsley has six goals and 19 points.

The Whitecaps are in a mild slump, having lost two of their last three games after winning eight straight. The team will be without six starters because of injuries, and Coach John Giles will be forced to start little-used Canadians Paul Nelson and Shaun Lowther on the back line.

Team America, attempting to break a five-game losing streak, is playing only the third game at home of the past eight. The team once led the Southern Division; now it is in last place with an 8-10 record and 56 points.

The final of the National Bank Embassy Cup will be held at RFK Stadium following the Team America-Vancouver game. The tournament is cosponsored by the National Bank of Washington and Team America.